Plus Size Decking: What is it, and is it Worth Your Money?

When it comes to decking lumber, there are usually two thicknesses available: 1 inch and 5/4 inch (which are usually referred to as 3/4” and 1” boards, respectively, despite these names being technically inaccurate in regards to the boards’ actual thicknesses). Recently, though, a third thickness has entered the market. These boards, which are referred to as plus size lumber, are usually 2 mm thicker than 3/4” boards (but still smaller than the 5/4” boards) and are marketed as being able to substantially increase a deck’s stability.

Plus size lumber is the standard size for lumber used for decks in most of Europe, a continent whose wet climate necessitates thicker wood for outdoor structures. However, some experts speculate that there is truly no need for this size lumber. Plus size lumber, they say, represents a classic example of a distributor finding a market (Europe) for a product (plus size boards) and trying to sell that product unnecessarily to other markets (America) in order to increase their profits.

Whatever the case, it’s definitely true that there are a few drawbacks to plus size lumber, so consider them carefully before you decide what kind of boards to use for your decking project.

It causes unnecessary waste.

To create plus size boards, most saw mills start with the same rough stock used to create 5/4” boards. However, because plus size boards (which, if you recall, are 2 mm thicker than 3/4” boards) are still smaller than 5/4” boards, they need to be sized down. This causes a great deal of unnecessary wood waste, something that many experts in the lumber industry find absolutely deplorable.

It will make it harder to do repairs in the future.

As mentioned above, plus size lumber is used primarily in decking projects in Europe. Although it is available in the United States, it is much less easy to come by on this side of the Atlantic. As a result, should your deck need any repairs or alterations, if you used plus size lumber, you could have a difficult task ahead of you. Not only will it be more difficult to locate than standard boards, but some lumber dealers also charge more for plus size boards because they are so uncommonly sized.

It might not add very much strength.

Despite lumber manufacturers’ claims that plus size boards significantly increase the strength of a deck, this may not be the case in many situations. Many decking lumbers are already incredibly strong, so strong, in fact, that plus size lumber is unlikely to make a difference.

Ipe lumber, for example, considered by lumber experts to be the best decking lumber available, is already unbelievably stable and rot resistant in the 3/4” thickness. Plus size lumber retailers say that the extra thickness adds necessary strength to Ipe and other types of lumber, but many in the industry question this claim. The experts at McIlvain Lumber Company, for example, one of the nation’s oldest and reputable lumber dealers, pose the following question:

“If you are installing a deck in such a hostile environment… is 2 mm really going to save the day?”

Because of the waste they create and the inconvenience of repairs involving plus size boards, it’s important to think carefully before you decide to use them in your decking project. The fact is, if 3/4” boards are too unstable for your project, then it’s probably best to simply make the jump to 5/4” boards, rather than putting your trust in the small amount of extra thickness- a mere 2 mm- provided by plus size boards.

McIlvain Company is one of the country’s top lumber dealers. With nationwide shipping and an enormous selection of both domestic and exotic lumbers, McIlvain is the best resource for all your lumber needs. And yes, despite disliking the waste that it creates, if you require plus size lumber for your project, they’ll even help you locate these uncommonly-sized boards.